In the semiconductor industry, reactors such as vapor phase reactors are used for example to etch films from semiconductor wafers or substrates. In a typical process, a gaseous etchant is admitted to the reactor chamber which will produce the desired chemistry to promote etching. The chamber can be operated at a range of pressures to further promote the reaction, and can also provide wafer heating for the same purpose.
Currently known reactors employ external heating of the chamber, by positioning heaters or lamps close to a transparent wall of the chamber. For example, U.S. Pat. No. 4,558,660 to Nishizawa, et al. entitled "Semiconductor Fabricating Apparatus" describes a quartz glass reaction tube for curing wafers in the presence of a gas, with the wafers being heated by lamps outside the reaction chamber. Cooling is provided either by channeling water through a reflective block positioned on the side of the lamps away from the chamber, or constructing a double-walled chamber and flowing a purified gas through the space in between the walls.
Other prior art using lamps external to the chamber includes: U.S. Pat. No. 5,305,416 to Fiory entitled "Semiconductor Processing Technique, Including Pyrometric Measurement of radiantly Heated Bodies;" U.S. Pat. No. 5,259,881 to Edwards, et al, entitled "Wafer Processing Cluster Tool Batch Preheating and Degassing Apparatus;" U.S. Pat. No. 5,027,746 to Frijlink entitled "Epitaxial Reactor Having a Wall Which is Protected from Deposits;" U.S. Pat. No. 4,533,820 to Shimuzu, entitled "Radiant Heating Apparatus;" U.S. Pat. No. 5,057,668 to Gisdakis, et al entitled "Device for the Implementation of a Curing Process at a Semiconductor Wafer and Method for Curing a Semiconductor Wafer;" and Japanese Patent 62-183513 to Natsuo, et al. entitled "Semiconductor Manufacturing Apparatus."
The prior art utilizes a heat source which is external to the chamber, and thus heating of the chamber is a relatively slow process. In addition, if more than a single wafer is to be processed, the wafers must be substantially coplanar so that the wafers face an array of lamps for even heating. Thus prior art methods are inefficient when large batches (for example 25 wafers in a wafer cassette) need to be processed, and processing time per wafer is very long.
Thus, there remains a need for a reactor that can rapidly heat the wafers inside before, during, or after the reaction process and be cooled down quickly afterwards for efficient processing of wafer batches.